Polyaniline Modified Electrode In Ionic Liquid Synthesis And Catalytic Electrochemical Reaction Of Bacteria On The Production Of Electric Impact

Electrochemistry and microbiology mode was employed to enrich the electricity producing bacteria from fresh water sediment bases on electricigens'metabolize mechanism in this thesis. The electricity producing bacteria was inoculated by generation and generation in substrate which electron acceptor is fumaric acid. The electrochemical polymerization of aniline on graphite electrode in a solution consisting of aniline, H₂SO₄ and ionic liquid (V/V), was performed at a constant potential. The character of the resulting product was identified by IR, UV-vis spectra and the cyclic voltammograms. The reactivity of graphite anode coated with PAn film was investigated in a MFC that have a shared cathode, the conclusions was presented as follows.1 Enrichment of electricigens from fresh water sedimentConstructing microbial fuel cell and by the substrate, the compact biofilm including electricigens attached on electrode was obtained. Some electricigens could use Fe³⁺,Mn⁴⁺ solid-state oxides acting as extracellular electron acceptors that receive electrons which coupled to the oxidation of organic matter in natural environments, therefore, electricigens which could reduce Fe³⁺ were selected by using the substrate that contain Ferric citrate. The electricigens were inoculated by generation and generation in substrate which electron acceptor is fumaric acid, in order to eliminating the interfering of Fe²⁺ and Fe³⁺ to electrode reactivity.Validating the electricigens'electrogenesis in MFC, it can produce electric current, obtaining the biofilm including bacteria and secretion attached on electrode simultaneity.2 Synthesizing and properties of Polyaniline/graphite electrodeThe electrochemical polymerization of aniline on graphite electrode in a solution consisting of 0.2M aniline, 2M H₂SO₄ and 0%, 10%, 20%, 30%, 40% ionic liquid(IL) (v/v), 1-ethyl-3-methylimidazolium ethyl sulfate (EMIES), was performed at a constant potential of 0.70V versus SCE for five and ten minutes respectively. Based on structure analysis of IR, UV-vis spectra, FE-SEM, the framework of the polyaniline synthesized in the solution that contain EMIES is similar to that of polyaniline synthesized in the H₂SO₄ solution. The IR spectrum of the PAnIL films which were prepared in the solutions containing aniline and various concentrations of the IL have a sharp and strong peak appears at 1380cm^-1 because the asymmetric stretching vibrations of SO₂ in R–O–SO₂–OR are in the range 1415–1380cm^-1. Therefore, the IR spectra show evidence that EMIES was incorporated into polyaniline.The cyclic voltammograms of these Polyaniline/graphite electrodes in 0.3M Na2SO4 solutions with different pH show that in the solutions of pH(3,4,5), them have identical electroactive; but The PAnIL synthesized in the solution containing 30% IL (v/v) shows the best redox activity in the solutions of pH(6,7,8,9,10,11). In the solutions of pH 7, the electrochemical activity of PAnIL increased 52.4% than PAn. The experiment also reveals that the electrochemical activity of the PAnIL synthesized in the solution containing 40% IL (v/v) was lower than the PAnIL synthesized in the solution containing 30% IL (v/v).The electrochemical polymerization of aniline was performed at a constant potential for five minutes, it's electrochemical activity was better than which performed for ten minutes. It was caused by the thickness of Polyaniline film on graphite electrodes. There were effect on H+ entering the film when the thickness of Polyaniline film was increased. In the Na2SO4 solution of pH 7, the electrochemical activity of the PAnIL synthesized in the solution containing 30% IL (v/v) for ten minute dropped 25%, compared to synthesized for five minutes.3 Performance and mechanism of MFC with Polyaniline/graphite anodeThere were constructing microbial fuel cells which have a shared cathode with these Polyaniline/graphite anodes which synthesized in solution containing 0%, 10%, 20%, 30%, 40% ionic liquid(v/v) for ten minutes. The MFC of PAnIL(30%)/graphite anode has the best performance, it's current increase 67% compared to the MFC of graphite anode and increase 30% compared to the MFC of PAn/graphite anode. The performance of MFCs of PAnIL(10%,20%,40%)/graphite anodes also are better than the MFCs of PAn/graphite anode and graphite anode in according to their electrochemical activity in 0.3M Na2SO4 solutions. The MFCs could produce current by replacing substrate in anode chamber, but the current is lower than before. It also obtained the electrode covered by bacteria. This explains that the electricigens used in the MFCs aren't single bacteria, they product current are caused by biofilm and electron shuttle mechanism.The experiment of these Polyaniline/graphite anodes which synthesized in the solution containing 0%, 10%, 20%, 30%, 40% ionic liquid(v/v) for five minutes in MFCs also shows that MFC of PAnIL(30%)/graphite anode has the best performance. It's current is 2.5 times of the MFC of graphite anode and increased 28.5% than the MFC of PAnIL(30%)/graphite anode synthesized for ten minutes. The respective activities of PAnIL(30%)/graphite anode synthesized for five and ten minutes in MFCs also in according to their electrochemical activity in 0.3M Na2SO4 solutions. This phenomenon may be caused by Polyaniline film on the electrode, the longer time synthesized , the thicker Polyaniline film, then restraining the electron transfer to some extent.